Magnetic core memories



United States Patent 3,210,745 MAGNETIC CORE MEMORIES Richard J. Dadamo, Drexel Hill, and William M. Hennessey, Roslyn, Pa., assignors to Burroughs Corporation, Detroit, Mich., a corporation of Michigan Filed Aug. 31, 1962, Ser. No. 220,744 10 Claims. (Cl. 340-174) This invention relates to magnetic core memory arrays.

Magnetic core memory arrays comprise, generally, an insulating frame which carries a large number of small toroidal magnetic cores through which a plurality of wires are threaded, the wires being secured to suitable electrical contact means on the frame. Assemblies of this type are known as memory planes, and, generally, a magnetic memory system is made up of a plurality of such memory planes connected together in a stack. The miniaturization of memory planes has raised problems which concern, among other things, the arrangement of contact members and terminals on the support frame, the securing of wires to these contacts, and the efficient electrical coupling of adjacent planes.

The objects of the present invention concern the provision of an improved magnetic core memory plane and memory array comprising a plurality of planes, the planes and array being of favorably small sizeand having an optimum construction providing electrical connections.

Briefly, the apparatus of the invention includes a plurality of memory planes, each of which comprises, essentially, an insulating frame which is provided with a plurality of electrical contact means to which are secured the various operating wires which are threaded through the usual array of miniature toroidal magnetic cores. The wires are secured directly to the electrical connection means provided on the insulating frames, and the latter means are shaped so that effective connection may be made thereto without the danger of short circuits developing between adjacent conductors. The connection means are also adapted to provide efficient and easy coupling between adjacent planes through simplified electrical clip means.

The invention is described in greater detail by reference to the drawing wherein:

FIG. 1 is a perspective view of a memory plane assembly embodying the invention;

FIG. 2 is a plan view of one of the FIG. 1; 'FIG. 3 is a plan view of the reverse side of the memory plane of FIG. 2;

FIG. 4 is a sectional view of a plane of FIG. 2;

FIG. 5 is a sectional view of a of FIG. 1;

FIG. 6 is a perspective view of a tool and associated apparatus used in preparing the memory plane assembly of the invention;

FIG. 7 is a sectional view of the tool shown in FIG. 6; and

FIG. 8 is a sectional view of the tool of FIG. 6 and the associated apparatus used in assemblying the memory assembly of the invention.

The present invention relates to a magnetic core memory system 10 which comprises a plurality of magnetic core memory planes 16 which are electrically and mechanically coupled together. Two such planes are shown in FIG. 1. Each memory plane 16 (FIGS. 2 and 3) comprises a generally rectangular frame 20 of a suitable insulating material which has an open central area 22 in which an array of toroidal magnetic cores 26 is positioned. The cores are supported on the frame by the various wires which are threaded through them and are secured to the frame. The insulating frame has top and bottom memory planes of portion of the memory portion of the assembly surfaces 30 and 32 and includes four side members 34, 36, 38, 40, each of which carries a plurality of electrical contact pads on both its top and bottom surfaces.

The contact pads are preferably formed by printed circuit techniques and, according to the invention, comprise alternating large-area and small-area members 44 and 48, respectively. Each large-area pad extends across substantially the entire width of a frame side and is generally L-shaped and includes a generally rectangular main body portion 50 and a projecting leg 52. Each small-area pad lies parallel to, and close to, the main body portion of the adjacent large-area pad and is similarly, rectangularly, shaped. The small-area pad is no wider than the projecting leg portion of the adjacent large-area pad and does not extend across the entire width of a frame side.

The above-described large-area and small-area pads alternate with each other along substantially the entire length of each side of each frame and on the top and bottom surfaces of each side, with large-area pads and small-area pads being vertically aligned on the top and bottom surfaces. With this arrangement of the pads, they may be spaced apart along the length of a side frame by as little as a few mils, and electrical connections may be made thereto without danger of electrical shorting. In particular, the staggered arrangement of the contact pads, that is, the alternation of the large-area and small-area pads, permit adjacent wires of the horizontal and vertical sets of wires to be staggered as follows.

Referring to FIGS. 2, 3, and 4, a typical horizontal wire X is soldered to a large-area pad 44 on frame side 34 and extends through a first row of cores 26 to an aligned small-area pad 48 on the opposite frame side 38. This small-area pad is electrically connected by means of a U-shaped connector 60 (FIG. 4), which passes through the frame, to a similar small-area pad 48' on the opposite surface. The U-shaped connector is soldered to both pads 48 and 48'. A wire X, which comprises an electrical continuation of the wire X, extends through a second row of cores 26' and terminates on a large-area contact pad 44 on the lower surface of the frame directly below the starting pad 44 on frame side 34. A second wire X2 originates at the next large-area pad 44 on the frame side 38 and extends through a first row of cores 26 to the opposite small-area pad 48 on frame side 34. This wire X2 is electrically connected through a U-shaped connector 60 to a small-area pad 48' on the bottom surface and then through a wire X2 and through a second row of cores 26' .to a large-area pad 44' positioned directly beneath the originating large-area pad on frame side 38. The third wire X3 originates at the next large-area pad on frame side 34-, and the fourth wire X4 originates at a large-area pad on the opposite frame side 38. The vertical wires Y are similarly secured and assembled on the rows of cores.

Other wires, such as sense and drive wires S and D, are also threaded thorugh the cores as required, with suitable contact pads 68 and '70 being provided on the frame sides for connection to the ends of these wires.

According to the invention, adjacent memory planes are secured together electrically, and mechanically, by a simple and efiicient means which comprises a plurality of flexible, metallic clips which are secured to facing arge-area contact pads 44 on adjacent memory planes as shown in FIGS. 1 and 5. The clips 80 are generally U-shaped and include a base 84 and side arms 88 and 90 which extend therefrom. The side arms 88 and 90 of the clips are suitably dimensioned to provide efficient, intimate, large-area contact with the pads 44 to which they are soldered.

In assembling the above-described magnetic memory core planes and arrays, the required wires X, S, D, etc. are threaded through the selected cores 26 in any suitable manner, and the ends of the wires are soldered to the proper contact pads. Individual memory planes 20 are then secured together by means of the metallic clips 80. For performing this operation, a tool 98 (FIGS. 6, 7, and 8) is provided which comprises essentially a supporting block having a generally trapezoidal cross-section (FIG. 7) including a top surface 102, a base 106, and side walls 110 and 114. The side walls 110 and 114 are suitably notched to receive the side arms 88 and 99 of a plurality of clips 80 (FIG. 8). The number of notches 120 is preferably equal to the number of clips to be secured to a frame 30.

A length of a suitable pressure-sensitive tape 124 is positioned on the top surface 102 of the tool, with its adhesive-covered surface up, and a plurality of clips 80 are positioned thereon with the bases 84 secured to the adhesive and with their side legs 88 and 9t) engaging notches 120. The required number of clips is secured to the tape 124. The tape carrying the clips is then removed from the tool 98, turned over, and is positioned between adjacent memory planes 20, with the side arms 88 and 90 of each clip in contact with opposed and aligned largearea contact pads 44. Thus positioned, the pressuresensitive tape faces up between the legs of the clips. The previously tinned side arms of each clip are then dipsoldered to the large-area pads, and an efficient and effective solder joint is thus formed, with securing solder 130 present between each arm of a clip and the adjacent contact pad. A strong, rigid connection is thus provided. The length of pressure-sensitive tape is then removed from the set of clips.

It has been found that, after the clips 80 have been soldered to adjacent memory planes 20, any mechanical distortion of a plane, such as concave or convex bowing, is corrected by the clips, and the planes are rendered flat and parallel to each other. A set of clips is thus provided between the adjacent sides of each plane.

The present invention provides a magnetic memory assembly which has many advantages. For one thing, the memory is strong and rugged and is relatively easy to assemble. In addition, it is'relatively easy to disassemble and repair since a plane may be readily removed by cutting the U-shaped clips. The repaired plane may be similarly readily returned to its position by means of a new set of clips, in the manner described above.

Because of these and the other features of the invention, it has been found that many hours can be saved in the construction, testing, and repair of a memory assembly. The U-shaped coupling clips also simplify the coupling of adjacent planes, and, as mentioned above, eliminate warpage which might be present. Another advantage of the invention arises from the fact that both sides of each memory plane carry electrical connections, and this, in conjunction with the large and small contact pads, allows solder joints to be spaced apart a greater distance than in the past, with resultant improved reliability and reduced possibility of electrical shorting.

What is claimed is: j

1. A magnetic core memory assembly comprising a plurality of memory planes coupled together,

each plane including a rectangular insulating plate having four edges and top and bottom surfaces,

a plurality of conductive contact elements extending along each edge of each insulating plate,

said contact elements comprising alternating large-area and small-area elements,

each large-area element including an edge portion positioned adjacent to one of said edges of said plate whereby contact from outside the plane and between one plane and another may be readily made,

each small-area element being oriented adjacent to a large-area element inwardly of an edge of said plate and shielded from an edge by said edge portion of a large-area element,

a separate array of magnetic core elements disposed on each of the top and bottom surfaces of each insulating plate in each memory plane, Y

and a plurality of parallel wires threaded through said cores and secured to said contact elements,

one wire originating at a large-area contact element at a first edge on the top surface of an insulating plate and extending: to a first small-area element at the opposite edge, to a second small-area element on the bottom surface at said opposite edge, to its termination in a large-area element on the bottom surface at said first edge,

the next adjacent wire originating at a large-area contact element at the opposite edge and on the top surface of the plate and extending: to a small-area element at said first edge on the top surface, to a small-area element at said first edge and on the bottom surface, and terminating at a large-area element at said opposite edge on the lower surface of the insulating plate.

2. The assembly defined in claim 1 wherein said largearea contact element is shaped to substantially enclose an adjacent small-area contact element and the maximum width of a large-area element defines the maximum width of an adjacent pair of small-area and large-area elements.

3. The assembly defined in claim 1 wherein said largearea contact element is generally L-shaped and includes an upstanding vertical portion and a horizontal base portion, and an adjacent small-area portion lies within the area defined by the base of the large-area element.

4. A magnetic core memory assembly comprising a plurality of separate memory planes coupled together,

each of said planes including top and bottom surfaces with conductive contact elements provided on both surfaces,

said conductive contact elements comprising alternating zones of relatively large-area and relatively smallarea, arrays of magnetic core elements electrically coupled to the contact elements on the top and bottom surfaces of each of said individual memory planes,

including in each plane a wire coupled from a largearea element on one surface of a plane through a plurality of magnetic cores to a small-area element at another location on said one surface and then through an aperture in the plane to a small-area element on the opposite surface and through a plurality of magnetic cores to its termination on a largearea contact element.

5. A magnetic core memory assembly comprising a plurality of separate memory planes coupled together,

each of said planes including top and bottom surfaces with conductive contact elements provided on both surfaces,

said conductive contact elements comprising alternating zones of relatively large-area and relatively smallarea, arrays of magnetic core elements electrically coupled to the contact elements on the top and bottom surfaces of each of said individual memory planes,

including in each plane a wire coupled from a largearea element on one surface of a plane through a plurality of magnetic cores to a small-area element at another location on said one surface and then through an aperture in the plane to a small-area element on the opposite surface and through a plurality of magnetic cores to its termination on a largearea contact element, and

conductive means coupled between adjacent planes and secured to facing large-area contact elements.

6. A magnetic core memory assembly comprising a plurality of separate memory planes coupled together,

each of said planes including top and bottom surfaces with conductive contact elements provided on both surfaces,

said conductive contact elements comprising alternating zones of relatively large-area and relatively smallarea,

arrays of magnetic core elements electrically coupled to the contact elements on the top and bottom surfaces of each of said individual memory planes,

including in each plane a Wire coupled from a largearea element on one surface of a plane through a plurality of magnetic cores to a small-area element at another location on said one surface and then through an aperture in the plane to a small-area element on the opposite surface and through a plurality of magnetic cores to its termination on a largearea contact element, and

conductive means coupled between adjacent planes and secured to facing large-area contact elements, said conductive means comprising U-shaped metal clips.

7. A magnetic core memory assembly comprising a plurality of separate memory planes coupled together,

each of said planes including top and bottom surfaces with conductive contact elements provided on both surfaces,

said conductive contact elements comprising alternating zones of relatively large-area and relatively smallarea,

arrays of magnetic core elements electrically coupled to the contact elements on the top and bottom surfaces of each of said individual memory planes,

including in each array of magnetic core elements a set of wires threaded through said cores, adjacent wires of said set being parallel to each other and originating, one at one region of and on the top surface of a plane and terminating on the bottom surface of a plane at said one region, and the next adjacent wire originating at a second region remote from said first region and on the top surface of the plane, said next adjacent wire terminating on the bottom surface of said plane at said second region, the wires of said set extending between said first and second regions of a plane.

8. A magnetic core memory assembly comprising a plurality of separate memory planes coupled totogether,

each plane being generally rectangular and having four side portions,

each of said side portions having top and bottom surfaces with conductive contact means provided on both surfaces of each of said side portions,

said conductive contact means comprising alternating zones of relatively large-area and relatively smallarea,

arrays of magnetic core elements electrically connected to the contact elements on the top and bottom surfaces of each of said individual memory planes, and

including in each plane a Wire coupled from a largearea element on one surface of a plane through a plurality of magnetic cores to a small-area element at another location on said one surface and then through an aperture in the plane to a small-area element on the opposite surface and through a plurality of magnetic cores to its termination on a largearea contact element.

9. A magnetic core memory assembly comprising a plurality of separate memory planes coupled totogether,

each plane being generally rectangular and having four side portions,

each of said side portions having top and bottom surfaces with conductive contact means provided on both surfaces of each of said side portions,

said conductive contact means comprising alternating zones of relatively large-area and relatively smallarea,

arrays of magnetic core elements electrically connected to the contact elements on the top and bottom surfaces of each of said individual memory planes,

including in each plane a wire coupled from a largearea element on one surface of a selected side portion of a plane through a plurality of magnetic cores to a small-area element on the same surface of the opposite side portion and then through an aperture in said opposite side portion to a small-area element on the opposite surface of said opposite side portion and through a plurality of magnetic cores to its termination on a large-area contact element on the opposite surface of said selected size portion, and

conductive means coupled between adjacent planes and secured to facing large-area contact elements.

10. A magnetic core memory assembly comprising and a plurality of separate memory planes coupled totogether,

each plane being generally rectangular and having four side portions,

each of said side portions having top and bottom surfaces with conductive contact means provided on both surfaces of each of said side portions,

said conductive contact means comprising alternating zones of relatively large-area and relatively smallarea,

arrays of magnetic core elements electrically connected to the contact elements on the top and bottom surfaces of each of said individual memory planes, and

including in each plane a first wire coupled from a large-area element on the top surface of a selected side portion of a plane through a plurality of magnetic cores to a small-area element on the top surface of the opposite side portion and then through an aperture in said opposite side portion to a smallarea element on the bottom surface of said opposite side portion and through a plurality of magnetic cores to its termination on a large-area contact element on the bottom surface of said selected side portion, and the neXt adjacent wire coupled from a large-area element on the top surface of the opposite side portion through a plurality of cores to a small-area element on the top surface of said selected side portion and through said selected side portion to a small-area element on the bottom surface thereof and finally through a plurality of cores to a large-area element on the bottom surface of said opposite side portion.

References Cited by the Examiner UNITED STATES PATENTS 2,934,748 4/60 Steimen 340174 IRVING L. SRAGOW, Primary Examiner, 

1. A MAGNETIC CORE MEMORY ASSEMBLY COMPRISING A PLURALITY OF MEMORY PLANES COUPLED TOGETHER, EACH PLANE INCLUDING A RECTANGULAR INSULATING PLATE HAVING FOUR EDGES AND TOP AND BOTTOM SURFACES, A PLURALITY OF CONDUCTIVE CONTACT ELEMENTS EXTENDING ALONG EACH EDGE OF EACH INSULATING PLATE, SAID CONTACT ELEMENTS COMPRISING ALTERNATING LARGE-AREA AND SMALL-AREA ELEMENTS, EACH LARGE-AREA ELEMENT INCLUDING AN EDGE PORTION POSITIONED ADJACENT TO ONE OF SAID EDGES OF SAID PLATE WHEREBY CONTACT FROM OUTSIDE THE PLANE AND BETWEEN ONE PLANE AND ANOTHER MAY BE READILY MADE, EACH SMALL-AREA ELEMENT BEING ORIENTED ADJACENT TO A LARGE-AREA ELEMENT INWARDLY OF AN EDGE OF SAID PLATE AND SHIELDED FROM AN EDGE BY SAID EDGE PORTION OF A LARGE-AREA ELEMENT, A SEPARATE ARRAY OF MAGNETIC CORE ELEMENTS DISPOSED ON EACH OF THE TOP AND BOTTOM SURFACES OF EACH INSULATING PLATE IN EACH MEMORY PLANE, AND A PLURALITY OF PARALLEL WIRES THREADED THROUGH SAID CORES AND SECURED TO SAID CONTACT ELEMENTS, ON WIRE ORIGINATING AT A LARGE-AREA CONACT ELEMENT 